CVE-2026-42040: Axios is a promise based HTTP client for the browser and Node.js

Q: How do I fix CVE-2026-42040?

axios: upgrade to 0.31.1, 1.15.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-42040 being exploited?

CVE-2026-42040 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-42040 affect?

CVE-2026-42040 affects axios. Severity is low (CVSS 3.7). Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function in lib/helpers/AxiosURLSearchParams.js contains a character mapping (charMap) at line 21 that reverses the safe percent-enco

Q: How urgent is CVE-2026-42040?

Priority 26/100. Public exploit reference; Remotely exploitable, no login, no user action

This week

LOW 3.7REMOTEUPGRADE

CVE-2026-42040 is a low-severity flaw (CVSS 3.7) affecting axios. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function in lib/helpers/AxiosURLSearchParams.js contains a character mapping (charMap) at line 21 that reverses the safe percent-encoding of null bytes. After encodeURIComponent('\x00') correctly produces the safe sequence %00, the charMap entry '%00': '\x00' converts it back to a raw null byte. Primary impact is limited because the standard

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-116, CWE-626
Published	2026-04-24
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: axios

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-24 18:16 UTCPublished CVE record published
2026-06-17 10:47 UTCUpdated Record last modified

axios axios UPGRADE

Affected: < 0.31.1 · >= 1.0.0 and < 1.15.1

Fixed in: 0.31.1, 1.15.1

Safe to downgrade to: a release before 1.0.0

1. Check installed version

npm ls axios

2. UPGRADE to 0.31.1

npm install axios@">=0.31.1"

3. If no update is available yet, DOWNGRADE to a release before 1.0.0

npm view axios versions npm install axios@"<1.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42040?

axios: upgrade to 0.31.1, 1.15.1. Exact commands for each OS are on this page.

Is CVE-2026-42040 being exploited?

CVE-2026-42040 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42040 affect?

CVE-2026-42040 affects axios. Severity is low (CVSS 3.7). Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function in lib/helpers/AxiosURLSearchParams.js contains a character mapping (charMap) at line 21 that reverses the safe percent-enco

How urgent is CVE-2026-42040?

Priority 26/100. Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Node.js vulnerabilities · Axios vulnerabilities

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References

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